Display element, photosensitive composition and electrowetting display

Abstract

The present invention relates to a display element, a photosensitive composition and an electrowetting display. The display element includes: a first electrode layer stack; a second electrode layer stack; a housing space formed between the first and second electrode layer stacks; and a partition wall compartmentalizing the housing space, wherein the housing space contains at least a polar liquid and a non-polar liquid that are immiscible with each other, a surface layer in contact with the partition wall exists on the surface of at least one of the first and second electrode layer stacks that is in contact with the housing space, and an absolute value of the difference in linear expansion coefficient between the partition wall and the surface layer is 150 ppm/K or less.

The invention claimed is: 
     
       1. A display element, comprising:
 a first electrode layer stack; 
 a second electrode layer stack, the first electrode layer stack and the second electrode layer stack facing each other to form a housing space therebetween; 
 a partition wall compartmentalizing said housing space; 
 a polar liquid and a non-polar liquid each disposed in the housing space and being immiscible with each other; and 
 a surface layer provided on a surface of at least one of the first and second electrode layer stacks and being in contact with said partition wall and in contact with at least one of the polar liquid and the non-polar liquid, 
 wherein a material of said partition wall and a material of said surface layer are selected such that an absolute value of a difference in thermal linear expansion coefficient between said partition wall and said surface layer is adjusted to 150 ppm/K or less. 
 
     
     
       2. The display element according to  claim 1 , wherein said partition wall has a thermal linear expansion coefficient of from 0.1 to 150 ppm/K. 
     
     
       3. The display element according to  claim 1 , wherein said partition wall is a film obtained from a photosensitive composition. 
     
     
       4. The display element according to  claim 1 , wherein said partition wall is a film obtained from a negative photosensitive composition. 
     
     
       5. The display element according to  claim 4 , wherein said negative photosensitive composition comprises an alkali-soluble polymer, a cross-linking agent and a photoinitiator. 
     
     
       6. The display element according to  claim 5 , wherein said cross-linking agent is at least one compound selected from the group consisting of an ethylenically unsaturated group-containing compound, an epoxy group or oxetanyl group-containing compound and an alkoxyalkyl group-containing compound. 
     
     
       7. The display element according to  claim 5 , wherein said alkali-soluble polymer comprises at least one functional group selected from the group consisting of a carboxyl group, a phenolic hydroxyl group and a silanol group. 
     
     
       8. The display element according to  claim 5 , wherein said alkali-soluble polymer is at least one polymer selected from the group consisting of an acrylic resin, a polyimide, a polybenzoxazole, a polysiloxane, a polyolefin, a cardo skeleton-containing resin and a novolac resin. 
     
     
       9. The display element according to  claim 5 , wherein said alkali-soluble polymer has a weight-average molecular weight of from 1,000 to 100,000. 
     
     
       10. An electrowetting display, comprising the display element according to  claim 1 . 
     
     
       11. The electrowetting display according to  claim 10 , further comprising a color filter layer. 
     
     
       12. The display element according to  claim 1 , wherein the partition wall has the thermal linear expansion coefficient of from 0.1 to 100 ppm/K. 
     
     
       13. The display element according to  claim 12 , wherein the material of said partition wall and the material of said surface layer are selected such that the absolute value of the-difference in thermal linear expansion coefficient between said partition wall and said surface layer is adjusted to 100 ppm/K or less. 
     
     
       14. The display element according to  claim 12 , wherein the partition wall comprises at least one polymer selected from the group consisting of an acrylic resin, a polyimide, a polybenzoxazole, a polysiloxane, a polyolefin, a cardo skeleton-containing resin and a novolac resin, and the surface layer comprises a fluorine-containing material. 
     
     
       15. The display element according to  claim 14 , wherein the material of said partition wall and the material of said surface layer are selected such that the absolute value of the difference in thermal linear expansion coefficient between said partition wall and said surface layer is adjusted to 100 ppm/K or less. 
     
     
       16. The display element according to  claim 12 , wherein the partition wall comprises at least one polymer selected from the group consisting of a cross-linked acrylic resin, a cross-linked polyimide, a cross-linked polybenzoxazole, a cross-linked polysiloxane, a cross-linked polyolefin, a cross-linked cardo skeleton-containing resin and a cross-linked novolac resin, and the surface layer comprises a fluorine-containing material. 
     
     
       17. The display element according to  claim 16 , wherein the material of said partition wall and the material of said surface layer are selected such that the absolute value of the-difference in thermal linear expansion coefficient between said partition wall and said surface layer is adjusted to 100 ppm/K or less. 
     
     
       18. A photosensitive composition for forming a partition wall of a display element, the display element comprising a first electrode layer stack and a second electrode layer stack which face each other to form a housing space therebetween, said partition wall compartmentalizing the housing space, a polar liquid and a non-polar liquid each disposed in the housing space and being immiscible with each other, and a surface layer provided on a surface of at least one of the first and second electrode layer stacks and being in contact with said partition wall and in contact with at least one of the polar liquid and the non-polar liquid,
 wherein components of said photosensitive composition and a material of said surface layer are selected such that an absolute value of a difference in thermal linear expansion coefficient between said partition wall and said surface layer is adjusted to 150 ppm/K or less. 
 
     
     
       19. The photosensitive composition according to  claim 18 , which is a negative composition comprising an alkali-soluble polymer, a cross-linking agent and a photoinitiator.